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O. L. LAWSON.

THREAD MEASURING DEVICE.

APPLICATION FILED APR. 22. I915.

Patented Aug. v15, 1916.

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OSCAR L. LAVISON, OF LYNN, MASSACHUSETTS, ASSIGNOB DE ONE-HALF T0 CARL ANDERSON, 0F LQVJELL, MASSACHUSETTS.

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Original application filed. May 29, 1914, Serial No. 841,752.

To all whom it may concern Be it known that I, OsoAi: ll. Lawson, a subject of the King of Sweden, residing at Lynn, county of Essex, State of Massachusetts, have invented a certain new and useful Improvement in 'llhread-llfeasuring Devices, of which the following is a specification, reference being had therein to the accompanying drawings.

This is a division of my prior application, Ser. TTO. 841,752, filed May 29, 191 1, for lock stitch sewing machine.

This invention relates to sewing machines for leather work and has particular reference to the combined tension and threrd lock and the thread measuring mechanisms for a sewing machine of the character described.

My improvements are designed with special reference toproviding a sewing machine which will be of low cost and effective for use by cobbler-s as well as for the general purposes to which leather sewing machines are put.

The invention will be fully understood from the following description taken in con nection with the accompanying drawings, and the novel features thereof will be pointed out and clearly defined in the claims at the close of the specification.

In the drawings, Figure 1 is a side elevation of the mechanism embodying my in vention. Fig. 2 is a view similar to Fig. 1 of the parts shown in the lower portion of Fig. 1, said parts being in a different position. Fig. 3 is a rear elevation of the parts shown in Fig, 2, said parts being in the position occupied by them as shown in Fig. 1.

Similar reference characters indicate the same or similar parts in all of the views.

In the drawings,at 35 is shown the presser foot supported on an arm 51 pivoted at 36 to a fixed part of the frame of the machine. At 21 is shown the main shaft, the same being rotated in time with the various working instrumentalities of the machine. These parts are in general old and well known and are further described in my prior application to which reference has heretofore been made.

The combined tension and thread lock comprising the subject matter of the present application for Letters Patent consists of a fixed pin 92 and a movable pin 93. The

fixed pin 92 has a thread guide aperture 94:

Specification of Letters Patent.

Patented ling. 115, 1916i.

Divided and this application filed April 22,

Serial No. 23,220.

indicated in dotted lines in Fig. 1 through which the thread passes from a suitable point of supply, not shown, the thread being wrapped once or more, if desired, around the pin 92 (see Fig. 2), then passing through suitable guides in a wax pot, then to suitable take-up mechanism and thence to the stitch forming mechanism. These instrumentalities form no part of my present inventi on and therefore are not shown. Detailed consideration and description thereof is also unnecessary. The pin 93 is carried by an elbow lever 98 pivotally supported at 99, said pin being held against the upper, preferably flattened, surface of the pin 92 by a suitably connected spring 100. A pendant arm 101 pivotally connected at 50 with the rear endof the arm- 51 of the presser foot has its lower end 102 wedge shaped, one edge of this wedge being adapted to engage a pin 103 projecting from a downwardly extending arm 104: of the elbow lever 98. The lower edge of the wedge 102 is adapted to be engaged by a pin 105 carried by a disk 58 on the shaft 21.

During the operation of the machine the presser foot 85 is periodically released and lifted slightly during the feed operation of the work by mechanism fully described in my prior application hereinbefore referred to. The presser foot'is also adapted to be lifted to a considerable extent for the insertion of the work. Whenever the presser foot 35 is raised, the wedge tip 102 is lowered. When the stock is thick the wedge will be lowered so that the pin 105 will act upon it as a cam and cause it to act on the pin 103 to raise pin 98 sooner and hold it up longer than when the stock is thin to allow more thread to be drawn freely by the take-up. The pin or cam 105 is so located that the time when it reaches the wedge 102 and causes the pin 93 to rise and open the thread clamp is when the take-up is acting to draw up enough thread for the next stitch.

When the presser foot 35 is to be raised for the introduction of the work the operator grasps the hand lever 64 and moves it in the direction of the arrow in Fig. 1. This open ates by mechanism described in my said prior application to lift the presser foot and lock it in raised position and the operator can then shift the work and pull 0E thread very readily. When the operator then wishes to resume sewing, the hand lever 64 is thrown back, resulting in restoring the presser foot to "the position shown in Fig. 1.

From the foregoing description it will be seen that each time the main shaft 21 revolves the movable pin 93 is raised above the fixed pin 92 a distance dependent upon the vertical position of the wedge 102 andthat thisvertical position of the Wedge 10:2 is in turn controlled by the position of the presser foot. Therefore the amount of thread delivered to the stitch forming mechanism is always correctly proportioned to the thickness of the stock which is momentarily being sewn.

At 106 is shown a fixed pin serving as an abutment to engage the lower end of the pendent member 101 so that if the presser foot is lifted at a 'time when the pin 105 on the disk 58 is not in contact with the pendent member the thread clamp will nevertheless be opened.

What I claim is:

1. In a sewing machine, a lever provided with a presser foot at one end thereof, a pendent lever pivotally connected to the said presser foot lever and having a wedge shaped lower end, said pendent lever being lowered by the rising of the presser foot, a lever carrying a thread clamping member at one end, the other end being in position to be engaged by the wedge shaped end of said pendent lever, and a rotary member having a projection which during its rotation is adapted to engage said wedge shaped porpresser foot, a lever carrying a thread clamping member at one end, the other end being in position to be engaged by the wedge shaped end of said pendent lever, and a rotary member having a projection which during its rotation is adapted to engage said wedge shaped portion of the pendent lever and to move it in a manner to turn the thread clamp lever and raise the thread clamp, the extent of elevation of the thread clamp being controlled by the extent of elevation of the presser foot and consequent depression of the wedge shaped pendent lever.

In testimony whereof I aifix my signature.

OSCAR L. LAWSON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

